Unrevoked - one click for those devices listed. There are also many, many other ways to root Android devices. Unrevoked is just an example and covers a lot of HTC's more popular devices.

Some Android phones even come pre-rooted. You don't need a cracked/unlocked bootloader unless you want to install custom ROMs or recoveries (you can't do that on an iPhone because Apple locks the shit up so bad LOLOLOL)